The Activation and Inhibition of Fibrinolysis
The mechanism of activation of the single chain proenzyme, plasminogen, to the two-chain disulfide linked protease, plasmin, is catalyzed by several activators. Any study of this mechanism must include the fact that at least two peptide bonds are cleaved in the activation process (1–3). Although most activators of plasminogen are proteases; the bacterial activator, streptokinase, possesses no proteolytic activity. Therefore, it becomes pertinent to inquire as to how two inactive proteins, i. e. plasminogen and streptokinase, can supposedly interact and result in the proteolytic cleavages required to convert plasminogen into plasmin. In this regard, it was found that streptokinase could form a 1:1 complex with human plasmin and this complex could directly activate plasminogen; a reaction that neither protein could catalyze independently (4–6). Further, this same activator complex was formed whether human plasmin or human plasminogen was used as one of the starting materials (6).
KeywordsCaproic Acid Amino Caproic Acid Plasminogen Activator Activity Conformational Alteration Human Plasminogen
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